De novo disruptive heterozygous MMP21 variants are potential predisposing genetic risk factors in Chinese Han heterotaxy children.

BACKGROUND: Heterotaxy syndrome (HTX) is caused by aberrant left-right patterning early in embryonic development, which results in abnormal positioning and morphology of the thoracic and abdominal organs. Currently, genetic testing discerns the underlying genetic cause in less than 20% of sporadic HTX cases, indicating that genetic pathogenesis remains poorly understood. In this study, we aim to garner a deeper understanding of the genetic factors of this disease by documenting the effect of different matrix metalloproteinase 21 (MMP21) variants on disease occurrence and pathogenesis. METHODS: Eighty-one HTX patients with complex congenital heart defects and 89 healthy children were enrolled, and we investigated the pathogenetic variants related to patients with HTX by exome sequencing. Zebrafish splice-blocking Morpholino oligo-mediated transient suppression assays were performed to confirm the potential pathogenicity of missense variants found in these patients with HTX. RESULTS: Three MMP21 heterozygous non-synonymous variants (c.731G > A (p.G244E), c.829C > T (p.L277F), and c.1459A > G (p.K487E)) were identified in three unrelated Chinese Han patients with HTX and complex congenital heart defects. Sanger sequencing confirmed that all variants were de novo. Cell transfection assay showed that none of the variants affect mRNA and protein expression levels of MMP21. Knockdown expression of mmp21 by splice-blocking Morpholino oligo in zebrafish embryos revealed a heart looping disorder, and mutant human MMP21 mRNA (c.731G > A, c.1459A > G, heterozygous mRNA (wild-type&c.731G > A), as well as heterozygous mRNA (wild-type& c.1459A > G) could not effectively rescue the heart looping defects. A patient with the MMP21 p.G244E variant was identified with other potential HTX-causing missense mutations, whereas the patient with the MMP21 p.K487E variant had no genetic mutations in other causative genes related to HTX. CONCLUSION: Our study highlights the role of the disruptive heterozygous MMP21 variant (p.K487E) in the etiology of HTX with complex cardiac malformations and expands the current mutation spectrum of MMP21 in HTX.

Treatment of pediatric lateral condylar humerus fractures with closed reduction and percutaneous pinning.

BACKGROUND: Lateral condylar humerus fractures (LCHFs) are the second most common pediatric distal humerus fractures. Open reduction and internal fixation is recommended for fractures displaced by more than 2 mm. Few studies described using closed reduction and percutaneous pinning (CRPP) for treating fractures with greater displacements. This study aims to explore the feasibility of CRPP in treating displaced LCHFs. METHODS: All patients underwent attempted CRPP first. Once a satisfying reduction was obtained, as determined using fluoroscopy based on the relative anatomical position of the fragments, an intraoperative arthrogram was performed to further confirm the congruence of the articular surface of the distal humerus. Open reduction is necessary to ensure adequate reduction if the fracture gap is more than 2.0 mm on either anteroposterior view or oblique internal rotational view by fluoroscopy after CRPP. All included fractures were treated by a single pediatric surgeon. RESULTS: Forty-six patients were included, 29 boys and 17 girls, with an average age of 5.2 years. Of these, 22/28 (78%) Jakob type II fractures and 14/18 (78%) Jakob type III fractures were treated with CRPP. All cases in Song stages II and III, 19/25 (76%) cases in Song stage IV, and 14/18 (78%) cases of Song stage V were treated with CRPP. The remaining converted to open reduction with internal fixation. Overall, 36 of the 46 patients (78%) were treated with CRPP. The average pre-op displacement was 7.2 mm, and the average post-op displacement was 1.1 mm on the anteroposterior or oblique internal rotational radiograph in cases treated with CRPP. CRPP was performed in an average of 37 min. The average casting period was 4 weeks and the average time of pin removal was 6 weeks postoperatively. The average time of follow-up was 4 months. All patients achieved union, regardless of closed or open reduction. No infection, delayed union, cubitus varus or valgus, osteonecrosis of the trochlea or capitellum, or pain were recorded during follow-up. CONCLUSIONS: Closed reduction and percutaneous pinning effectively treats LCHFs with displacement more than 4 mm. More than 3/4 of Song stage V or Jakob type III patients can avoid an incision.

Genome-wide profiling of mRNA and lncRNA expression in dengue fever and dengue hemorrhagic fever.

Dengue fever (DF) and dengue hemorrhagic fever (DHF) are recurrent diseases that are widespread in the tropics. Here, we identified candidate genes associated with these diseases by performing integrated analyses of DF (GSE51808) and DHF (GSE18090) microarray datasets in the Gene Expression Omnibus (GEO). In all, we identified 7635 differentially expressed genes (DEGs) in DF and 8147 DEGs in DHF as compared to healthy controls (P < 0.05). In addition, we discovered 215 differentially expressed long non-coding RNAs (DElncRNAs) in DF and 225 DElncRNAs in DHF. There were 1256 common DEGs and eight common DElncRNAs in DHF vs DF, DHF vs normal control, and DF vs normal control groups. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that signal transduction (false discovery rate = 8.33E-10), 'toxoplasmosis', and 'protein processing in endoplasmic reticulum' were significantly enriched pathways for common DEGs. We conclude that the MAGED1,STAT1, and IL12A genes may play crucial roles in DF and DHF, and suggest that our findings may facilitate the identification of biomarkers and the development of new drug design strategies for DF and DHF treatment.

Levels of vitamin D receptor and CYP24A1 in patients with end-stage renal disease.

OBJECTIVE: This study was performed to detect the expression of vitamin D receptor (VDR) and cytochrome P450, family 24, subfamily A, polypeptide 1 (CYP24A1) in 24 end stage renal disease (ESRD) patients and 24 healthy controls. METHOD: In this study, 24 ESRD patients and 24 healthy controls were included. RESULTS: In our study, the levels of VDR in patients with ESRD were reduced when compared with those from healthy controls (5.20±0.32 vs 8.59±1.03; P<0.01). However, the levels of CYP24A1 in ESRD patients were increased than those from healthy controls (50.18±21 vs 7.78±1.31; P<0.01). Correlation analysis showed that VDR levels were negatively correlated with CYP24A1 (r=-0.723; P<0.01). CONCLUSION: VDR levels were reduced and CYP24A1 levels were increased in patients with ESRD, and VDR levels were negatively correlated with CYP24A1.

Synthesis and evaluation of a 18F-labeled spirocyclic piperidine derivative as promising σ1 receptor imaging agent.

Several spirocyclic piperidine derivatives were designed and synthesized as σ1 receptor ligands. In vitro competition binding assays showed that the fluoroalkoxy analogues with small substituents possessed high affinity towards σ1 receptors and subtype selectivity. Particularly for ligand 1'-((6-(2-fluoroethoxy)pyridin-3-yl)methyl)-3H-spiro[2-benzofuran-1,4'-piperidine] (2), high σ1 receptor affinity (Ki=2.30 nM) and high σ1/σ2 subtype selectivity (142-fold) as well as high σ1/VAChT selectivity (234-fold) were observed. [18F]2 was synthesized using an efficient one-pot, two-step reaction method in a home-made automated synthesis module, with an overall isolated radiochemical yield of 8-10%, a radiochemical purity of higher than 99%, and specific activity of 56-78GBq/µmol. Biodistribution studies of [18F]2 in ICR mice indicated high initial brain uptake and a relatively fast washout. Administration of haloperidol, compound 1 and different concentrations of SA4503 (3, 5, or 10 µmol/kg) 5 min prior to injection of [18F]2 significantly decreased the accumulation of radiotracer in organs known to contain σ1 receptors. Ex vivo autoradiography in Sprague-Dawley rats demonstrated high accumulation of radiotracer in brain areas with high expression of σ1 receptors. These encouraging results prove that [18F]2 is a suitable candidate for σ1 receptor imaging with PET in humans.